SICB 2020: How is Light Effecting Behavior and Physiology of Anoles?

Urbanization is becoming a huge concern and many researchers at SICB 2020 wanted to study the effects it has on the surrounding wildlife. Laura Taylor, an undergraduate student at Trinity University, looked specifically at how urbanization and artificial light at night (ALAN) effected both the physiology and the behavior of anoles.

Green anoles (Anolis carolinensis), captured from the wild, were randomly placed into the control or experimental trial. Anoles in the control room were under a 14 hour light and 10 hour dark cycle to simulate a summer day. Experimental anoles were housed under the same conditions, with one important difference, they were exposed to a “streetlight” that remained on from dusk to dawn to simulate a real-world anthropogenic disturbance. Several smaller studies were done throughout the duration of the project to understand ALAN’s effects on both behavior and physiology. These included observing activity behaviors during both day and night, noting which anoles were more likely to eat their cricket during the day .vs. at midnight, and measuring their testes and fat pad size to determine how physiology was being impacted.

Anoles exposed to ALAN were more likely to be at rest during the day and moving slower compared to at night when they were awake, moving more, as well as moving quicker (could this be indicating a shift in the organism from diurnal to nocturnal?). The experimental anole groups were also the only ones to consume crickets at midnight, supporting previous studies that ALAN anoles can exploit a foraging niche in the wild created by ambient light. Moving towards the results from the physiology studies, ALAN anoles were found to have been maintaining their mass, having larger fat pads, and larger testes. The explanation? The seasonal photoperiods (which signals the decrease in testes size over the summer) were disrupted and led to a loss of that signal, leaving the ALAN anoles to maintain their larger testes size. Their large fat pads and mass maintenance are supportive of previous studies done in mammals, begging the question, how is artificial light at night affecting humans?

 

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Featured image: “Carolina anole Lizard” by berduchwal is licensed under CC BY 2.0